Hey BAS, was this to upgrade an older flat screen to a "smart tv" or for a different app you needed on your existing one didn't have access to - Hulu/Youtube/NetFlix/Plex Tv/HBO GO /MLB Tv etc?
I use plex myself, but through Roku not chromecast so not sure I can be of much help on this one. Plex requires you to be running a server from your computer of your movie files you've downloaded or you must have access to another users server through invitation so its not just a movie free-for-all so to speak. I think chromecast has a similar service for free called VideoStream. You can stream anything from your computer to tv that way. Not sure what apps might be other than old movie stuff on Crackle (download that for some classics stuff) and there are other apps that have free content and pay content.
-murph